Vegetation cutting implements known as mower cutting decks are typically carried by compact utility tractors, other utility vehicles, lawn and garden tractors or zero turn mowers. These vehicles have mower deck lift linkages allowing adjustment of the decks between a range of heights above ground level. Ordinarily, the range extends between a position at or below the lowest available cutting height to a position at or above the highest available cut height. Adjustment to a position below the cutting height range is frequently preferred for ease in installation or removal of the deck from the vehicle because the deck is at or very close to the ground surface. Adjustment above the cut height range may permit the deck to clear obstacles encountered while traveling across the ground. This maximum height may be referred to as the deck transport position.
Adjustment of the cutting deck height may be accomplished by various mechanisms including hand-operated levers and bars positioned in the vicinity of the tractor's or mower's operator station. The height of cut control systems require an operator to either push or pull on a lever or bar to adjust the deck height. Pedal actuated mechanisms also are used to adjust cutting deck height relative to the vehicle frame, and may include a handle or other hardware which automatically locks the mower deck in a given position upon full actuation of the pedal.
Examples of height of cut control systems for mower decks include U.S. Pat. No. 4,120,136 for “Implement Supporting and Lifting Linkage”; U.S. Pat. No. 5,138,825 for “Riding Mower Having a Pedal Operated Height Adjustment Mechanism, Air Assisted Discharge, and Improved Hydrostatic Shift Linkage”; U.S. Pat. No. 5,187,925 for “Mower Deck Lift System Handle Mechanism”; U.S. Pat. No. 5,351,467 for “Height Adjustment Mechanism for Riding Mower Cutting Deck”; U.S. Pat. No. 5,381,648 for “Mower Deck Height Adjustment Mechanism”: U.S. Pat. No. 5,797,252 for “Height of Cut Adjustment Mechanism”; U.S. Pat. No. 5,816,033 for “Riding Lawn Mower Including a Mower Deck Height Control Mechanism”; U.S. Pat. No. 5,946,893 for “Lawn Mower Having Cutter Deck Motion Coupled to Mower Wheel Motion”; U.S. Pat. No. 6,427,430 for “Pedal Lift System for Lawn Tractor Mower Deck”; U.S. Pat. No. 6,494,028 for “Deck Lift Apparatus for Riding Mower”; U.S. Pat. No. 6,588,188 for “Foot Lift Cutter Deck Mower Units”; U.S. Pat. No. 6,837,032 for “Pedal Actuated Height Adjustment Mechanism for a Mower Cutting Deck”; U.S. Pat. Nos. 7,448,191 and 7,614,207 for “Mower Deck Lift System with Transport Lock”; and U.S. Pat. No. 7,716,906 for “Single Lever Mower Deck Height-Of-Cut Control.”
Height of cut control systems with linear actuators have been proposed for mower decks. For example, patents describing linear actuators include U.S. Pat. No. 3,948,024 for “Implement Position Control System”; U.S. Pat. No. 4,663,923 for Self-Propelled Mower”; Japanese Application No. JP-H1-174307A; Japanese Application No. JP-H1-179616A; Japanese Application No. JP-H10-42654A; Japanese Application No. JP-H5-260838A; and U.S. Pat. No. 7,146,786 for “Electric Linear Deck Lift Assembly”. These height of cut control systems include linear drive rods, positional sensors and/or linear potentiometers to move mower decks to desired cutting heights. However, mower decks have a tendency to shift away from desired cutting heights due to wear over time or impacts with objects. As a result, height of cut control systems may lose accuracy of cutting height during normal use. A height of cut control system is needed that can adjust or return a mower deck to the desired cutting height while mowing. A height of cut control system also is needed that provides visual feedback to the operator showing if the actual height of the mower deck is off the desired cutting height.
In the past, height of cut control systems have required raising the mower deck off a stop before changing the desired cutting height. A height of cut control system is needed that allows an operator to move the mower deck to various different cutting heights while continuing to mow.